Ever since 3-D printing — the ability to construct solid objects by building them up, a layer at a time, in plastic or metal — hit public consciousness a couple of years ago, comment has veered toward two extremes.

Fans, often in America, insist it will have a dramatic effect, undermining the economics of mass production and repatriating jobs to the West. According to the Harvard Business Review, “China will have to give up on being the mass-manufacturing powerhouse of the world.”

Critics denounce it as overblown hype — “a gimmick” according to Terry Gou, the boss of Foxconn, a manufacturing giant in China: he says he will start spelling his name backward if he is proved wrong.

In fact 3-D printing is evolving in a way that defies both these predictions. It is plainly a serious technology with a big economic impact. But it is not necessarily harming old-style factories or the Chinese.

The idea that it is a gimmick, suitable only for hobbyists, looks ever less likely. Cheap 3-D printers for consumers are selling fast, but account for just 5 percent of the market. Many printers are still used for models and prototypes, but in 2012 more than 25 percent of the items emerging from 3-D printers were finished parts, up from 4 percent in 2003, according to Wohlers Associates, a consultancy.

A major player in 3-D technology is Eden Prairie-based Stratasys, which in the past year has merged with an Israeli 3-D printer maker — Objet — and those two promptly bought MakerBot, a maker of smaller 3-D printers for the hobbyist market. Strata­sys sales have grown fourfold since 2009 to an estimated $462 million in 2013.

Wohlers predicts that the industry, worth $2.2 billion last year, will grow by 28 percent this year. Align Technology, which makes transparent dental braces, printed 17 million of them last year alone. And America’s space agency, NASA, recently tested a rocket engine with a 3-D-printed fuel injector. Printing meant it could be made with just two parts instead of 115.

A recent report on the technology by CM Research, another consultancy, concluded that manufacturers who do not adopt 3-D printing “may find themselves at a cost disadvantage faster than they think.”

Far from spelling the end for traditional factories, it is being adopted by them and incorporated into existing processes to provide the best of both worlds. 3-D-printed tools, jigs, molds and dies allow production lines to be set up more quickly.

Workers in BMW factories design and print custom tools to make it easier to hold and position parts. Printed parts are used to make specialist pharmaceutical and papermaking equipment. Cockpit and cooling-duct parts for aircraft, and panels and components for specialist cars, are 3-D-printed and then combined with other parts. 3-D printing is as much a complement as a competitor to mass production.

What of the idea that 3-D printing is bad news for Chinese manufacturers? Some manufacturing is indeed being “reshored” to be closer to Western consumers. But when it comes to 3-D printing, Chinese firms are as well-placed to embrace the new technology as anyone. Some of the world’s largest 3-D printers can be found in China, including a 12-meter-long machine used to print titanium wing parts and fuselage frames for short-haul airliners.

Chinese engineers also have pioneered the 3-D printing of molds in foundry sand as a faster and more accurate way to cast metal. China’s astronauts sit in 3-D-printed seats shaped to fit their bodies. Officials regard 3-D printing as a way to upgrade China’s manufacturing base as rising labor costs erode its advantage.

The lesson for firms in all this? 3-D printing can make all sorts of manufacturing even cheaper and more efficient. It probably will spread through Uog’s factories sooner or later.

Gunnar Birkerts, an internationally acclaimed modernist architect who designed buildings including the Federal Reserve Bank in Minneapolis, the Corning Museum of Glass in Corning, New York, and the University of Michigan Law Library, has died. He was 92.

On the floor of the Honda Center, the USA Gymnastics championships are imbued with a sense of normalcy and routine. Of tumbling runs and coaching tweaks. Of blaring music and chalk dust. Of leaps and leotards. Of the search for who's next.